MP4Box is a MP4 multiplexer. It can import MPEG-4 video, DivX, XviD, 3ivX, H.264 etc, audio streams and subtitles into the .MP4 container. The end result is a compliant MP4 stream. It can also extract streams from a MP4. MP4Box is a command line tool, but can be used with graphical user interfaces such as YAMB.